Communication apparatus and communication method

ABSTRACT

A mobile communication system in which a mobile station apparatus transmits reception quality information to a base station apparatus, the reception quality information indicating quality of a signal received from the base station apparatus, characterized in that the base station apparatus transmits information for instructing transmission of reception quality information without uplink data included in an uplink data transmission permission signal, and the mobile station apparatus transmits reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data. This allows a mobile station apparatus to transmit reception quality information including a large amount of information even if there is no uplink data between the mobile station apparatus and the base station apparatus, and the transmission control flexibly responding to the amount of information and the frequency of transmissions of the reception quality information transmitted from the mobile station apparatus is possible. Therefore, more efficient communication control (scheduling) between the base station apparatus and the mobile station apparatus can be achieved.

CROSS-REFERENCE

This Application is a Divisional of co-pending application Ser. No. 12/529,042 filed Aug. 28, 2009, which claims priority on PCT International Application No. PCT/JP2008/065848 filed Sep. 3, 2008 under 35 U.S.C § 120. This Application also claims priority under 35 U.S.C § 119 on Japanese Application No. JP 2007-231154 filed Sep. 6, 2007. The entire contents of each of these applications are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a communication technique, and particularly, to a mobile communication system in which a mobile station apparatus measures reception quality of a signal received from a base station apparatus to transmit reception quality information to the base station apparatuses, and relates to a base station apparatus and a mobile station apparatus which are adapted to the mobile communication system.

BACKGROUND ART

Recently, demand for data communication is increasing in a mobile communication system, and various techniques are proposed to obtain high frequency use efficiency meeting the increase in the communication data associated with the demand. One of the techniques for increasing the frequency use efficiency is OFDMA (Orthogonal Frequency Division Multiple Access). The OFDMA relates to a technique of modulation method of communication in which the same frequency is used in all cells in a communication area constituted by the cells, and the OFDMA can achieve fast data communication. In the scheduling of transmission packets in the OFDMA system, a method is known in which mobile station apparatuses transmit CQI (Channel Quality Indicator), which is information indicating the reception quality of a downlink state for sub-carriers in wideband, to a base station apparatus, and the base station apparatus performs scheduling of the packets based on the CQI of sub-carriers in wideband transmitted from the mobile station apparatuses.

Furthermore, in the scheduling of transmission packets in an OFDM (Orthogonal Frequency Division Multiplexing) system using a plurality of sub-carriers, a technique is also known in which mobile station apparatuses evaluate each channel states of a downlink (frequency characteristics, or characteristics such as transmission loss dependent on the frequency) and transmit information with quantized each channel states to a base station apparatus, and the base station apparatus determines sub-carriers to be assigned to the mobile station apparatuses based on the transmitted information (see, Patent Document 1 below). FIG. 5 is a diagram showing an overview of a conventional communication method between a base station apparatus and a mobile station apparatus. FIG. 5(A) is a diagram showing a system configuration example, and FIG. 5(B) is a diagram showing a characteristic example. Having received downlink information 205 of a downlink line used for reception quality measurement from a base station apparatus 201, a mobile station apparatus measures the reception quality of each channel (FIG. 5(B)) based on the downlink information and quantizes the measured reception quality of each channel to create a channel profile of a propagation path.

The channel profile created by the mobile station apparatus 203 is transmitted, from the mobile station apparatus 203 to the base station apparatus 201, as reception quality information 207 using an uplink line. The base station apparatus 201 executes processing, such as adaptive modulation and coding or frequency selective scheduling, upon signals transmitted from the base station apparatus 201 to the mobile station apparatus 203 based on the reception quality information 207.

In relation to the transmission of reception quality information by the mobile station apparatus to the base station apparatus, transmission from the mobile station apparatus to the base station apparatus by using a dedicated uplink control channel (hereinafter, referred to as PUCCH (Physical Uplink Control Channel)) and an uplink shared data channel (hereinafter, PUSCH (Physical Uplink Shared Channel)) is examined in the evolution of third generation wireless access (Evolved Universal Terrestrial Radio Access) examined in 3GPP (3rd Generation Partnership Project) that is an international standardization project. For example, Non-Patent Document 1 described below proposes transmitting the reception quality information using the PUCCH or the PUSCH depending on the type of services, in which required reception quality information varies, when the mobile station apparatus transmits the reception quality information to the base station apparatus.

Patent Document 1: JP Patent Publication (Kokai) No. 2005-130491A

Non-Patent Document 1: “CQI handling during DRX”, 3GPP, TSG RAN WG2 Meeting #58, R2-071901, May 2007

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, in the above conventional technique, uplink data and reception quality information needed to be transmitted at the same time when the mobile station apparatus transmits the reception quality information using the PUSCH. Thus, there was a problem that the mobile station apparatus could not transmit the reception quality information using the PUSCH if there was no uplink data to be transmitted to the base station apparatus. In general, since the resource region assigned as the PUCCH is smaller than the resource region assigned as the PUSCH, the amount of information of the reception quality information that can be transmitted using the PUCCH is small. On the other hand, the reception quality information transmitted using the PUSCH is reception quality information including a large amount of information.

The base station apparatus performs processing, such as adaptive modulation and coding or frequency selective scheduling, upon the signals to be transmitted to the mobile station apparatus based on the reception quality information transmitted from the mobile station apparatus. When the mobile station apparatus transmits reception quality information including a small amount of information using the PUCCH, the base station apparatus does not execute processing, such as highly accurate adaptive modulation and coding or frequency selective scheduling, in accordance with the amount of information, or executes only the processing of adaptive modulation and coding to transmit signals to the mobile station apparatus. When the mobile station apparatus transmits reception quality information including a large amount of information using the PUSCH, the base station apparatus executes processing, such as highly accurate adaptive modulation and coding or frequency selective scheduling, based on the information to transmit signals to the mobile station apparatus.

In this way, when the reception quality information transmitted from the mobile station apparatus includes a large amount of information, the base station apparatus can perform processing, such as highly accurate adaptive modulation and coding or frequency selective scheduling, upon the signals to be transmitted. As a result, the communication control (scheduling) between the base station apparatus and the mobile station apparatus can be more efficiently performed.

There are various types of services performed between the mobile station apparatus and the base station apparatus, such as VoIP (voice call), WEB browsing, and TV phone. One of the services is a service of continuing to download a large amount of data (UDP packets) such as moving images, and in that case, there is no uplink data to be transmitted from the mobile station apparatus to the base station apparatus.

Thus, in the conventional technique, the mobile station apparatus cannot transmit the reception quality information including a large amount of information using the PUSCH in a service in which a great amount of data (UDP packets), such as moving images, is continuously downloaded without the uplink data. This means that the base station apparatus cannot perform processing, such as highly accurate adaptive modulation and coding or frequency selective scheduling, upon the signals to be transmitted in the case of services without the uplink data, and that the communication control (scheduling) between the base station apparatus and the mobile station apparatus cannot be more efficiently performed.

Furthermore, in the conventional technique, there was no specific description of what kind of control information the base station apparatus uses to control the mobile station apparatus when the mobile station apparatus transmits only the reception quality information using the PUSCH, and what kind of exchange is made between the base station apparatus and the mobile station apparatus to transmit the reception quality information. In the transmission of the reception quality information by the mobile station apparatus to the base station apparatus, there is a demand that the base station apparatus controls the amount of information and the frequency of transmissions of the reception quality information transmitted from the mobile station apparatus. The base station apparatus should control the amount of information and the frequency of transmissions of the transmitted reception quality information in consideration of the uplink resource in the cell controlled by the base station apparatus. If large-sized reception quality information is frequently transmitted based on the decision of each mobile station apparatus, the uplink source in the cell becomes scarce, and if small-sized reception quality information is transmitted infrequently, the uplink resource is wasted. Thus, when the mobile station apparatus transmits the reception quality information to the base station apparatus, what kind of control information the base station apparatus uses to control the mobile station apparatus and what kind of exchange is made between the base station apparatus and the mobile station apparatus to transmit the reception quality information are important issues. An efficient transmission control method is needed in which the amount of information and the frequency of transmissions of the reception quality information to be transmitted are taken into account.

The present invention has been made in view of the foregoing circumstances, and an object of the present invention is to provide a mobile communication system, a base station apparatus, and a mobile station apparatus which can transmit reception quality information including a large amount of information from a mobile station apparatus even if there is no uplink data between the mobile station apparatus and the base station apparatus, and perform transmission control flexibly responding to the amount of information and the frequency of transmissions of the reception quality information transmitted from the mobile station apparatus to achieve more efficient communication control (scheduling) between the base station apparatus and the mobile station apparatus.

Means for Solving the Problems

(1) The present invention provides a mobile communication system in which a mobile station apparatus transmits reception quality information to a base station apparatus, the reception quality information indicating quality of a signal received from the base station apparatus, characterized in that the base station apparatus transmits information for instructing transmission of reception quality information without uplink data included in an uplink data transmission permission signal, and the mobile station apparatus transmits reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data.

(2) The mobile communication system is characterized in that the mobile station apparatus transmits, to the base station apparatus, the reception quality information using an uplink shared data channel.

(3) The present invention provides a mobile communication system in which a mobile station apparatus transmits reception quality information to a base station apparatus using an uplink shared channel, the reception quality information indicating quality of a signal received from the base station apparatus, characterized in that the base station apparatus transmits information for instructing transmission of reception quality information without uplink data included in an uplink data transmission permission signal, and the mobile station apparatus transmits reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data.

(4) The present invention provides a mobile communication system in which a mobile station apparatus transmits reception quality information to a base station apparatus, the reception quality information indicating quality of a signal received from the base station apparatus, characterized in that the base station apparatus transmits information for instructing transmission of reception quality information without uplink data included in an uplink data transmission permission signal, the mobile station apparatus transmits reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data; and at this time; and at this time, in case that ACK or NACK for downlink data needs to be transmitted, transmits reception quality information and ACK or NACK without uplink data.

(5) The mobile communication system is characterized in that the mobile station apparatus transmit, to the base station apparatus, the reception quality information and the ACK or the NACK using an uplink shared data channel.

(6) The present invention provides a mobile communication system in which a mobile station apparatus transmits reception quality information to a base station apparatus using an uplink shared channel, the reception quality information indicating quality of a signal received from the base station apparatus, characterized in that the base station apparatus transmits information for instructing transmission of reception quality information without uplink data included in an uplink data transmission permission signal, the mobile station apparatus transmits reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data; and at this time, in case that ACK or NACK for downlink data needs to be transmitted, transmits, to the base station apparatus, reception quality information and ACK or NACK without uplink data.

(7) The mobile communication system is characterized in that the information for indicating transmission of reception quality information without uplink data is represented by using information for instructing transmission of reception quality information and information constituting an uplink data transmission permission signal.

(8) The mobile communication system is characterized in that the information constituting the uplink data transmission permission signal is HARQ redundancy version information.

(9) The mobile communication system is characterized in that the information constituting the uplink data transmission permission signal is MCS information.

(10) The mobile communication system is characterized in that the information constituting the uplink data transmission permission signal is transport block size information.

(11) The present invention provides a base station apparatus in a mobile communication system in which a mobile station apparatus transmits reception quality information to the base station apparatus, the reception quality information indicating quality of a signal received from the base station apparatus, the base station apparatus characterized by comprising: means for transmitting information for instructing transmission of reception quality information without uplink data included in an uplink data transmission permission signal to the mobile station apparatus.

(12) The present invention provides a base station apparatus in a mobile communication system in which a mobile station apparatus transmits reception quality information to the base station apparatus using an uplink shared channel, the reception quality information indicating quality of a signal received from the base station apparatus, the base station apparatus characterized by comprising: means for transmitting information for instructing transmission of reception quality information without uplink data included in an uplink data transmission permission signal to the mobile station apparatus.

(13) The base station apparatus is characterized in that the information for instructing transmission of reception quality information without uplink data is represented by using information for information for instructing transmission of reception quality information without uplink data transmission of reception quality information and information constituting an uplink data transmission permission signal.

(14) The base station apparatus is characterized in that the information constituting the uplink data transmission permission signal is HARQ redundancy version information.

(15) The base station apparatus is characterized in that the information constituting the uplink data transmission permission signal is MCS information.

(16) The base station apparatus is characterized in that the information constituting the uplink data transmission permission signal is transport block size information.

(17) The present invention provides a mobile station apparatus in a mobile communication system a mobile station apparatus in a mobile communication system in which the mobile station apparatus transmits reception quality information to a base station apparatus, the reception quality information indicating quality of a signal received from the base station apparatus, the mobile station apparatus characterized by comprising: means for receiving an uplink data transmission permission signal including information for instructing transmission of reception quality information without uplink data from the base station apparatus; and means for transmitting reception quality information without uplink data to the base station apparatus according to the information for instructing transmission of reception quality information without uplink data.

(18) The mobile station apparatus is characterized in that the means for transmitting reception quality information to the base station apparatus transmits the reception quality information using an uplink shared data channel.

(19) The present invention provides a mobile station apparatus in a mobile communication system in which the mobile station apparatus transmits reception quality information to a base station apparatus using an uplink shared channel, the reception quality information indicating quality of a signal received from the base station apparatus, the mobile station apparatus characterized by comprising: means for receiving an uplink data transmission permission signal including information for instructing transmission of reception quality information without uplink data from the base station apparatus; and means for transmitting reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data to the base station apparatus.

(20) The present invention provides a mobile station apparatus in a mobile communication system in which the mobile station apparatus transmits reception quality information to a base station apparatus, the reception quality information indicating quality of a signal received from the base station apparatus, the mobile station apparatus characterized by comprising: means for receiving an uplink data transmission permission signal including information for instructing transmission of reception quality information without uplink data from the base station apparatus; and means for transmitting reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data to the base station apparatus, wherein in case that ACK or NACK for downlink data needs to be transmitted when transmitting reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data, the means for transmitting the reception quality information to the base station apparatus transmits the reception quality information and the ACK or the NACK without uplink data.

(21) The mobile station apparatus is characterized in that the means for transmitting the reception quality information to the base station apparatus transmits, to the base station apparatus, the reception quality information and the ACK or the NACK using an uplink shared data channel.

(22) The present invention provides a mobile station apparatus in a mobile communication system in which the mobile station apparatus transmits reception quality information to a base station apparatus using an uplink shared channel, the reception quality information indicating quality of a signal received from the base station apparatus, the mobile station apparatus characterized by comprising: means for receiving an uplink data transmission permission signal including information for instructing transmission of reception quality information without uplink data from the base station apparatus; and means for transmitting reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data to the base station apparatus, wherein in case that ACK or NACK for downlink data needs to be transmitted when transmitting reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data, the means for transmitting the reception quality information to the base station apparatus transmits reception quality information and ACK or the NACK without uplink data.

(23) The mobile station apparatus is characterized in that the information for instructing transmission of reception quality information without uplink data is represented by using information for instructing transmission of reception quality information and information constituting an uplink data transmission permission signal.

(24) The mobile station apparatus is characterized in that the information constituting the uplink data transmission permission signal is HARQ redundancy version information.

(25) The mobile station apparatus is characterized in that the information constituting the uplink data transmission permission signal is MCS information.

(26) The mobile station apparatus is characterized in that the information constituting the uplink data transmission permission signal is transport block size information.

ADVANTAGES OF THE INVENTION

According to the present invention, a mobile station apparatus can transmit reception quality information including a large amount of information even if there is no uplink data between the mobile station apparatus and a base station apparatus, and the transmission control flexibly responding to the amount of information and the frequency of transmissions of the reception quality information transmitted from the mobile station apparatus is possible. Therefore, more efficient communication control (scheduling) between the base station apparatus and the mobile station apparatus can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram showing a configuration of a base station apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic block diagram showing a configuration of a mobile station apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining a processing flow of a modified example of the first embodiment of the present invention.

FIG. 4 is a diagram for explaining a second embodiment of the present invention and a processing flow.

FIG. 5 is a diagram for explaining a general communication method of a base station apparatus and a mobile station apparatus.

DESCRIPTION OF SYMBOLS

A . . . base station apparatus, B . . . mobile station apparatus, 27 . . . transmission information control unit, 27 a . . . scheduler unit, 27 b . . . modulation encoding control unit, 27 c . . . frequency scheduler unit, 63 . . . reception quality information control unit, 63 a . . . reception quality information generating unit, 63 b . . . reception quality measuring unit.

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment

First, a mobile communication system according to a first embodiment of the present invention will be described. The mobile communication system according to the present embodiment includes a base station apparatus and a mobile station apparatus and has a configuration similar to that in FIG. 5(A). FIG. 1 is a functional block diagram showing a schematic configuration example of the base station apparatus according to the present embodiment. As shown in FIG. 1, a base station apparatus A comprises a data control unit 1, a modulation encoding unit 3, a mapping unit 5, an inverse fast Fourier transform (IFFT) unit 7, a wireless transmitting unit 11, a wireless receiving unit 15, a fast Fourier transform (FFT) unit 17, a demodulation decoding unit 21, a data extraction unit 23, a transmission information control unit 27, and an antenna 31. The transmission information control unit 27 includes a scheduler unit 27 a, a modulation and coding control unit 27 b, and a frequency selective scheduler unit 27 c.

In the base station apparatus A, transmission data and control data to be transmitted to each mobile station apparatus are inputted to the data control unit 1, and the data is sequentially transmitted to the mobile station apparatuses according to an instruction from the transmission information control unit 27. The modulation encoding unit 3 performs a modulation processing or an error correction coding processing upon a signal outputted from the data control unit based on modulation scheme and coding rate determined by the transmission information control unit 27 and outputs the data to the mapping unit. The mapping unit maps the data outputted from the modulation encoding unit 3 on each sub-carrier based on frequency selective scheduling information outputted from the transmission information control unit 27 and outputs the data to the inverse fast Fourier transform unit 7.

The inverse fast Fourier transform unit 7 performs a processing of inverse fast Fourier transform upon the data outputted from the mapping unit 5, converts the data to a time-series baseband digital signal, and outputs the signal to the wireless transmitting unit 11. The wireless transmitting unit 11 performs digital/analog conversion of the output signal from the inverse fast Fourier transform unit 7, up-converts the signal to a frequency suitable for transmission, and then transmits the signal to each mobile station apparatus through the antenna.

The scheduler unit 27 a schedules the downlink and the uplink based on control information, such as a resource region that each mobile station apparatus can use, an intermittent transmission reception cycle, a format of transmission data channel, and a buffer status. The modulating and coding control unit 27 b determines the modulation scheme and the coding rate to be applied to each data based on the reception quality information transmitted from the mobile station apparatus. The frequency selective scheduler unit 27 c executes a processing of frequency selective scheduling to be applied to each data based on the reception quality information transmitted from the mobile station apparatus. The data extraction unit 23 separates demodulated and decoded data into reception data for user and control data, transfers the data to a superior processing unit, and outputs the reception quality information to the transmission information control unit 27.

FIG. 2 is a functional block diagram showing a schematic configuration example of a mobile station apparatus according to the first embodiment of the present invention. As shown in FIG. 2, a mobile station apparatus B comprises a data control unit 41, a modulation encoding unit 43, a mapping unit 45, an inverse fast Fourier transform (IFFT) unit 47, a wireless transmitting unit 51, a wireless receiving unit 53, a fast Fourier transform (FFT) unit 55, a demodulation decoding unit 57, a data extraction unit 61, a reception quality information control unit 63, and an antenna 65. The reception quality information control unit 63 comprises a reception quality information generating unit 63 a and a reception quality measuring unit 63 b.

The wireless receiving unit 53, the FFT unit 55, the demodulation decoding unit 57, the data extraction unit 61, and the reception quality information control unit 63 constitute a receiving unit as a whole, and the data control unit 41, the modulation encoding unit 43, the mapping unit 45, the inverse fast Fourier transform (IFFT) unit 47, and the wireless transmitting unit 51 constitute a transmitting unit as a whole.

In the mobile station apparatus B shown in FIG. 2, transmission data and control data to be transmitted to the base station apparatus A are inputted to the data control unit 41, and the data is sequentially transmitted to the base station apparatus. The modulation encoding unit 43 performs a modulation processing or an error correction coding processing upon a signal outputted from the data control unit 41 and outputs the data to the mapping unit 45. The mapping unit 45 maps the data outputted from the modulation encoding unit 43 on each sub-carrier and outputs the data to the inverse fast Fourier transform unit 47.

The inverse fast Fourier transform unit 47 performs a processing of inverse fast Fourier transform upon a symbol sequence outputted from the mapping unit 45, converts the symbol sequence to a time-series baseband digital signal, and outputs the signal to the wireless transmitting unit 51. The wireless transmitting unit performs digital/analog conversion to the output signal from the inverse fast Fourier transform unit 47, up-converts the signal to a frequency suitable for transmission, and then transmits the signal to the base station apparatus A through the antenna.

The reception quality measuring unit 63 b measures the reception quality of a signal received from the base station apparatus A. The reception quality information generating unit 63 a generates reception quality information to be transmitted to the base station apparatus A based on the information measured by the reception quality measuring unit 63 b.

FIG. 3 is a diagram for explaining a communication technique according to the first embodiment of the present invention. A diagram on the left side of FIG. 3 illustrates control signals (L1/L2 grants) transmitted from the base station apparatus to the mobile station apparatus, reception quality information, uplink data, and transmission forms of information transmitted in uplink, and a diagram on the right side illustrates a processing flow corresponding to the slots. In FIG. 3, operations from #slot1 to #slot12 are illustrated as an example.

The mobile station apparatus B transmits data using PUSCH according to resource assignment indicated by a downlink control channel (hereinafter, PDCCH (Physical Downlink Control Channel)) from the base station apparatus A. Thus, the downlink control channel (PDCCH) is a signal for permitting data transmission in the uplink (uplink data transmission permission signal, “L1/L2 grant” hereinafter). The L1/L2 grant is constituted by, for example, resource assignment information (10 bits), MCS (Modulation and Coding Scheme) (2 bits), transport block size (6 bits), HARQ (Hybrid Automatic Repeat Request) redundancy version (2 bits), demodulation pilot signal strength (2 bits), and mobile station identification information C-RNTI (16 bits).

In the first embodiment of the present invention, the base station apparatus A includes reception quality information-dedicated transmission permission information, which is for permitting the mobile station apparatus B to transmit only the reception quality information using a resource assigned by the L1/L2 grant, in the L1/L2 grant including reception quality information transmission permission information which is for permitting the mobile station apparatus B to transmit the reception quality information, and transmits the L1/L2 grant. Having received the signal, the mobile station apparatus B transmits, to the base station apparatus A, only the reception quality information using the resource assigned by the L1/L2 grant (corresponding to #slot4, #slot7, and #slot12 in FIG. 3).

The operations in the slots will be described with reference to FIG. 3.

In #slot2, the base station apparatus A, which has determined to instruct the mobile station apparatus B to transmit the reception quality information, transmits the L1/L2 grant in which the permission information (hereinafter, referred to as “reception quality information transmission permission information”) is set equal to, for example, “1”, to the mobile station apparatus B (71). Hereinafter, in the embodiments of the present invention, the reception quality information transmission permission information is represented by, for example, 1 bit information, and the base station apparatus transmits the L1/L2 grant by setting “1” when permitting the transmission of the reception quality information, or by setting “0” to avoid transmitting the reception quality information. In the present embodiment, although such a setting is employed for simplifying the description, it is obvious that other setting methods can be used. Having received the L1/L2 grant in which the reception quality information transmission permission information is set equal to “1”, the mobile station apparatus B simultaneously transmits, to the base station apparatus A, the reception quality information and the uplink data using the resource assigned by the L1/L2 grant (72).

In #slot3, the base station apparatus A transmits a normal L1/L2 grant to the mobile station apparatus B (73), and the mobile station apparatus B that has received the signal transmits, to the base station apparatus A, the uplink data using the resource assigned by the L1/L2 grant (74).

Next, an operation of #slot 4 will be described.

In #slot4, the base station apparatus A, having determined to permit the mobile station apparatus B to transmit only the reception quality information, transmits the L1/L2 grant in which the designation information (hereinafter, referred to as “reception quality information-dedicated transmission permission information”) is set equal to, for example, “1”, to the mobile station apparatus B (75). Hereinafter, in the embodiments of the present invention, the reception quality information-dedicated transmission permission signal is represented by, for example, 1 bit information, and the base station apparatus transmits the L1/L2 grant by setting “1” when permitting the transmission of only the reception quality information, or by setting “0” to avoid transmitting only the reception quality information. In the present embodiment, although such a setting is employed for simplifying the description, it is obvious that other setting methods can be used. Having received the L1/L2 grant in which the reception quality information-dedicated transmission permission information is set equal to “1”, the mobile station apparatus B transmits, to the base station apparatus A, only the reception quality information using the assigned resource (76). However, the mobile station apparatus B transmits the reception quality information and ACK/NACK in case that the ACK/NACK of HARQ for the downlink data needs to be transmitted.

The L1/L2 grants transmitted from the base station apparatus in #slot2, #slot3, and #slot4 in the first embodiment will be further described. In the L1/L2 grants transmitted in #slot2, #slot3, and #slot4, the reception quality information transmission permission information and the reception quality information-dedicated transmission permission information are always included. Thus, the L1/L2 grants always include 2 bit information. In the 2 bit information, the base station apparatus sets the reception quality information transmission permission information equal to “1” and the reception quality information-dedicated transmission permission information equal to “0” in #slot2 and sets the reception quality information transmission permission information equal to “0” and the reception quality information-dedicated transmission permission information equal to “0” in #slot3. The base station apparatus sets the reception quality information transmission permission information equal to “1” and the reception quality information-dedicated transmission permission information equal to “1” in #slot4. In the explanation of slot2, #slot3, and #slot4 described above, although only information set equal to “1” is described for simplifying the explanation, the L1/L2 grants always include 2 bit information of the reception quality information transmission permission information and the reception quality information-dedicated transmission permission information in the first embodiment. Hereinafter, in the explanation of the embodiments of the present invention, only information set equal to “1” will be basically described for simplifying the explanation.

FIG. 3 similarly illustrates that the base station apparatus A transmits the L1/L2 grants in which the reception quality information transmission permission information is set equal to “1” in #slot6, #slot9, and #slot10, and that the mobile station apparatus B that has received the signals simultaneously transmits, to the base station apparatus A, the reception quality information and the uplink data using the assigned resources (78, 82, and 84). FIG. 3 also illustrates that the base station apparatus transmits a normal L1/L2 grant in #slot11, and that the mobile station apparatus B that has received the signal transmits, to the base station apparatus A, the uplink data using the assigned resource (86). FIG. 3 further illustrates that the base station apparatus transmits L1/L2 grants in which the reception quality information-dedicated transmission permission information is set equal to “1” to the mobile station apparatus B in #slot7 and #slot12, and the mobile station apparatus that has received the signals transmits, to the base station apparatus A, only the reception quality information (80 and 88). In #slot7 and #slot12, only the reception quality information is transmitted to the base station apparatus A even if there is uplink data in the information transmitted by the mobile station apparatus B using the uplink.

In FIG. 3, numerals 105 to 140 indicate the existence of data in the slots. The illustration of the L1/L2 grants depicted with horizontal hatches for #slot2, #slot6, #slot9, and #slot10 indicates that the base station apparatus A transmits L1/L2 grants in which the reception quality information transmission permission information is set equal to “1” and the reception quality information-dedicated transmission permission information is set equal to “0”. The illustration of the L1/L2 grants depicted in black for #slot4, #slot7, and #slot12 indicates that the base station apparatus A transmits L1/L2 grants in which the reception quality information transmission permission information is set equal to “1” and the reception quality information-dedicated transmission permission information is set equal to “1”.

The illustration of the transmission forms depicted with diagonal lines (equivalent to reception quality information) and white frames (equivalent to uplink data) for #slot2, #slot6, #slot9, and #slot10 indicates that the mobile station apparatus B simultaneously transmits, to the base station apparatus A, the reception quality information and the uplink data. The illustration of the transmission forms depicted in lattice pattern for #slot4, #slot7, and #slot12 indicates that the mobile station apparatus B transmits, to the base station apparatus A, only the reception quality information.

The processing flow corresponding to the slots will be described with reference to the diagram on the right side of FIG. 3.

In #slot2, the base station apparatus A transmits an L1/L2 grant in which the reception quality information transmission permission information is set equal to “1” (71). Receiving the signal, the mobile station apparatus B simultaneously transmits the reception quality information and the uplink data using the assigned resource (72). The same processing is executed in #slot6, #slot9, and #slot 10.

In #slot3, the base station apparatus A transmits a normal L1/L2 grant (73). Receiving the signal, the mobile station apparatus B transmits the uplink data using the assigned resource (74). The same processing is executed in #slot11.

In #slot4, the base station apparatus A transmits an L1/L2 grant in which the reception quality information-dedicated transmission permission information is set equal to “1” (75). Receiving the signal, the mobile station apparatus B transmits, to the base station apparatus, only the reception quality information using the assigned resource (76). In #slot7 and #slot12, only the reception quality information is transmitted to the base station apparatus A even if there is uplink data in the information transmitted by the mobile station apparatus B using the uplink.

The reception quality information-dedicated transmission permission information included in the L1/L2 grant can be represented by other information included in the L1/L2 grant without adding a new information bit. For example, all values of HARQ redundancy versions for the uplink data included in the L1/L2 grants can be set equal to 0, all values of MCS for the uplink data can be set equal to 0, or the transport block size for the uplink data can be set equal to 0 to represent the reception quality information-dedicated transmission permission information. The fact that these values are set equal to 0 denotes that the L1/L2 grants from the base station apparatus indicate that there is no need to transmit anything in the uplink data transmitted from the mobile station apparatus. The mobile station apparatus that has received the signal recognizes that the L1/L2 grant from the base station apparatus is not a normal L1/L2 grant and transmits only the reception quality information to the base station apparatus.

Thus, in #slot4, #slot7, and #slot12 of FIG. 3, the L1/L2 grants in which all values of the HARQ redundancy versions for the uplink data are set equal to 0, all values of MCS for the uplink data are set equal to 0, or the transport block size for the uplink data is set equal to 0, is transmitted from the base station apparatus A, and the mobile station apparatus B that has received the signal transmits, to the base station apparatus A, only the reception quality information using the resources assigned by the L1/L2 grants. In that case, the reception quality information transmission permission information is set equal to “1”. Which information included in the L1/L2 grants transmitted from the base station apparatus A will be used, and with what way of setting in the information the mobile station apparatus B will transmit only the reception quality information are determined in advance in specifications or the like, and this is known information between the base station apparatus A and the mobile station apparatus B. In this way, there is no need to add a new information bit to the L1/L2 grant as the reception quality information-dedicated transmission permission information as a result of using other information included in the L1/L2 grant to represent the reception quality information-dedicated transmission permission information, and the mobile station apparatus B can transmit only the reception quality information to the base station apparatus A without increasing the amount of information included in the L1/L2 grant.

As described, according to the first embodiment of the present invention, the base station apparatus transmits an L1/L2 grant including reception quality information-dedicated transmission permission information that permits transmission of only the reception quality information, and the mobile station apparatus that has received the signal transmits only the reception quality information to the base station apparatus. As a result, the mobile station apparatus can transmit only the reception quality information.

The mobile station apparatus can transmit reception quality information including a large amount of information because the resource assigned by the L1/L2 grant including the reception quality information-dedicated transmission permission information from the base station apparatus is used to transmit the reception quality information. As a result, for example, the mobile station apparatus can transmit the reception quality information including a large amount of information even in a service in which a great amount of data (UDP packets), such as moving images, is continuously downloaded without uplink data.

Furthermore, since the reception quality information-dedicated transmission permission information, which permits the mobile station apparatus to transmit only the reception quality information, is included in the L1/L2 grant and transmitted to the mobile station apparatus, the base station apparatus can control how often the mobile station apparatus transmits only the reception quality information.

This allows transmission control flexibly responding to the amount of information and the frequency of transmissions of the reception quality information transmitted from the mobile station apparatus, and more efficient communication control (scheduling) between the base station apparatus and the mobile station apparatus can be achieved.

Second Embodiment

FIG. 4 is a diagram for explaining a communication technique according to a second embodiment of the present invention. A diagram on the left side of FIG. 4 illustrates control signals (L1/L2 grants) transmitted from the base station apparatus to the mobile station apparatus, reception quality information, uplink data, and transmission forms of information transmitted in uplink, and a diagram on the right side illustrates a processing flow corresponding to the slots. In FIG. 4, operations from #slot1 to #slot12 are illustrated as an example.

In the second embodiment of the present invention, the base station apparatus transmits RRC signaling including reception quality information transmission instruction information to the mobile station apparatus. The base station apparatus also transmits an L1/L2 grant including reception quality information transmission permission information which permits the mobile station apparatus to transmit, the reception quality information, to the mobile station apparatus. The reception quality information transmission instruction information herein is, as described below, information for designating to use the reception quality information transmission permission information (information for designating to transmit the reception quality information) as the reception quality information-dedicated transmission permission information (information for designating to transmit only the reception quality information). Numerals 161 to 199 have similar meaning as in FIG. 3.

The operations in the slots will be described with reference to FIG. 4.

Prior to #slot1, it is designated in the reception quality information transmission instruction information in the RRC signaling from the base station apparatus A that the mobile station apparatus B should transmit the reception quality information to the base station apparatus whenever an L1/L2 grant in which the reception quality information transmission permission information is set equal to “1” is received.

As described also in the first embodiment, the base station apparatus A, which has determined in #slot2 to instruct the mobile station apparatus B to transmit the reception quality information, transmits an L1/L2 grant in which the reception quality information transmission permission information is set equal to “1”, to the mobile station apparatus B (141). Having received the L1/L2 grant including the reception quality information transmission permission information, the mobile station apparatus B simultaneously transmits, to the base station apparatus A, the reception quality information and the uplink data using the resource assigned by the L1/L2 grant (142). In #slot3, the base station apparatus A transmits a normal L1/L2 grant to the mobile station apparatus B (143), and the mobile station apparatus B that has received the signal transmits, to the base station apparatus A, the uplink data using the resource assigned by the L1/L2 grant (144).

FIG. 4 similarly illustrates that the base station apparatus A transmits L1/L2 grants in which the reception quality information transmission permission information is set equal to “1”, in #slot4 and #slot6, and the mobile station apparatus B that has received the signal simultaneously transmits, to the base station apparatus, the uplink data and the reception quality information using the assigned resources (146 and 148).

Next, an operation of #slot8 will be described.

In #slot8, the base station apparatus A designates the mobile station apparatus B to use the reception quality information transmission permission information as the reception quality information-dedicated transmission permission information, by the RRC signaling including the reception quality information transmission instruction information (149).

The reception quality information transmission instruction information will be described here. In the present second embodiment, the mobile station apparatus B that has received the RRC signaling including the reception quality information transmission instruction information interprets the reception quality information transmission permission information included in the L1/L2 grant transmitted from the base station apparatus A as the reception quality information-dedicated transmission permission information. For example, if the base station apparatus A represent the reception quality information transmission permission information by an information bit “A”, information represented by the same information bit “A” serves as the reception quality information-dedicated transmission permission information after the RRC signaling including the reception quality information transmission instruction information is received.

This point will be described using FIG. 4.

In FIG. 4, it is assumed that the base station apparatus sets the information bit “A”, which represents the reception quality information transmission permission information, equal to “1” in #slot2, #slot4, and #slot6 to permit the mobile station apparatus to transmit the reception quality information. Having received the signal, the mobile station apparatus B simultaneously transmits the reception quality information and the uplink data. The base station apparatus A transmits the RRC signaling including the reception quality information transmission instruction information in #slot8 (149). The base station apparatus A can further set the same information bit “A”, which represents the reception quality information transmission permission information, equal to “1” in #slot9, #slot10, and #slot12 to permit the mobile station apparatus B to transmit only the reception quality information. Thus, the reception quality information transmission permission information and the reception quality information-dedicated transmission permission information represented as 2 bit information in the first embodiment can be combined into the same one information (information bit “A”) by transmitting the RRC signaling. It can also be stated that the reception quality information transmission instruction information included in the RRC signaling from the base station apparatus A is information for switching the interpretation from the reception quality information transmission permission information to the reception quality information-dedicated transmission permission information.

In #slot9 of FIG. 4, the base station apparatus A transmits an L1/L2 grant in which the reception quality information transmission permission information is set equal to “1”, and the mobile station apparatus B that has received the signal transmits, to the base station apparatus A, only the reception quality information although there is uplink data in the information transmitted using the uplink (153). Thus, in the slot after the RRC signaling including the reception quality information transmission instruction information is transmitted, the mobile station apparatus B that has received the L1/L2 grant in which the reception quality information transmission permission information is set equal to “1” does not transmit the uplink data to the base station apparatus A even if there is uplink data in the information transmitted using the uplink. In FIG. 4, the mobile station apparatus B that has received the L1/L2 grant in which the reception quality information transmission permission information is set equal to “1”, similarly transmits only the reception quality information to the base station apparatus in #slot12 (157).

The #slot10 illustrates that the base station apparatus A transmits the L1/L2 grant in which the reception quality information transmission permission information is set equal to “1”, to the mobile station apparatus B (152), and that the mobile station apparatus B that has received the signal transmits, to the base station apparatus A, only the reception quality information using the resource assigned by the L1/L2 grant (153).

In #slot11, the base station apparatus A transmits a normal L1/L2 grant to the mobile station apparatus B (154), and the mobile station apparatus B that has received the signal transmits, to the base station apparatus A, the uplink data using the resource assigned by the L1/L2 grant (155).

Next, a processing flow corresponding to the slots will be described.

In #slot2, the base station apparatus A transmits an L1/L2 grant in which the reception quality information transmission permission information is set equal to “1” (141). Having received the signal, the mobile station apparatus B simultaneously transmits the reception quality information and the uplink data using the assigned resource (142). The same processing is executed in #slot4 and #slot6.

In #slot3, the base station apparatus transmits a normal L1/L2 grant (143). Having received the signal, the mobile station apparatus B transmits the uplink data using the assigned resource (144). The same processing is executed in #slot11.

In #slot8, the base station apparatus A transmits RRC signaling including reception quality information transmission designation information (149) to designate that the reception quality information transmission permission information be used as the reception quality information-dedicated transmission permission information. Having received the signal, the mobile station apparatus B determines the reception quality information transmission permission information as the reception quality information-dedicated transmission permission information in the subsequent slots (switches the interpretation).

In #slot9, the base station apparatus A transmits an L1/L2 grant in which the reception quality information transmission permission information is set equal to “1” (150). Having received the signal, the mobile station apparatus B transmits, to the base station apparatus A, only the reception quality information using the assigned resource although there is uplink data in the information to be transmitted using the uplink (151). The same processing is executed in #slot 12.

In #slot10, the base station apparatus A transmits an L1/L2 grant in which the reception quality information-dedicated transmission permission information is set equal to “1” (152). Having received the signal, the mobile station apparatus B transmits, to the base station apparatus A, only the reception quality information using the assigned resource (153).

As described, according to the second embodiment of the present invention, the base station apparatus transmits the RRC signaling including the reception quality information transmission designation information and designates the mobile station apparatus that has received the signal to use the reception quality information transmission permission information as the reception quality information-dedicated transmission permission information. As a result, the mobile station apparatus B can transmit only the reception quality information to the base station apparatus A without increasing the amount of information included in the L1/L2 grant.

The mobile station apparatus can transmit the reception quality information including a large amount of information since the resource assigned by the L1/L2 grant including the reception quality information transmission permission information from the base station apparatus is used to transmit the reception quality information. As a result, for example, the mobile station apparatus can transmit the reception quality information including a large amount of information even in a service in which a great amount of data (UDP packets), such as moving images, is continuously downloaded without uplink data.

Furthermore, since the reception quality information transmission permission information that permits the mobile station apparatus to transmit the reception quality information is included in the L1/L2 grant and transmitted to the mobile station apparatus, the base station apparatus can control how often the mobile station apparatus transmits the reception quality information.

This allows transmission control flexibly responding to the amount of information and the frequency of transmissions of the reception quality information transmitted from the mobile station apparatus, and more efficient communication control (scheduling) between the base station apparatus and the mobile station apparatus can be achieved.

The RRC signaling including the reception quality information transmission instruction information from the base station apparatus in the second embodiment of the present invention is transmitted when, for example, the service performed between the mobile station apparatus and the base station apparatus switches from a normal service in which uplink data exists, to a service in which a great amount of data (UDP packets), such as moving images, is continuously downloaded without a great volume of uplink data.

All embodiments of the present invention can also be applied to the transmit diversity such as SDM (Space Division Multiplexing) using MIMO communication (Multiple Input Multiple Output), SFBC (Space-Frequency Block Diversity), and CDD (Cyclic Delay Diversity). The reception quality information in the present embodiment includes the number of streams that the mobile station apparatus can receive in the MIMO communication (RANK information) and index information indicating information of preprocessing (Pre-coding) performed in advance to correctly separate a plurality of streams transmitted from the base station apparatus (PMI (Pre-coding Matrix Index) information).

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configurations are not limited to the embodiments, and designs and the like that do not depart from the scope of the invention are also included in the claims.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a communication apparatus. 

1. A mobile communication system in which a mobile station apparatus transmits reception quality information to a base station apparatus, the reception quality information indicating quality of a signal received from the base station apparatus, characterized in that the base station apparatus transmits, to the mobile station apparatus, an uplink data transmission permission signal including information for indicating transmission of reception quality information without uplink data, the mobile station apparatus transmits, to the base station apparatus, reception quality information without uplink data in case that the information for instructing transmission of reception quality information without uplink data is included in the uplink data transmission permission signal; and at this time, in case that ACK or NACK for downlink data needs to be transmitted, transmits, to the base station apparatus, reception quality information and ACK or NACK without uplink data.
 2. The mobile communication system according to claim 1, characterized in that the mobile station apparatus transmits, to the base station apparatus, the reception quality information and the ACK or NACK using a physical uplink shared channel.
 3. A mobile communication system in which a mobile station apparatus transmits reception quality information to a base station apparatus using a physical uplink shared channel, the reception quality information indicating quality of a signal received from the base station apparatus, characterized in that the base station apparatus transmits, to the mobile station apparatus, an uplink data transmission permission signal including information for instructing transmission of reception quality information without uplink data, the mobile station apparatus transmits, to the base station apparatus, reception quality information without uplink data in case that the information for instructing transmission of reception quality information without uplink data is included in the uplink data transmission permission signal; and at this time, in case that ACK or NACK for downlink data needs to be transmitted, transmits, to the base station apparatus, reception quality information and ACK or NACK without uplink data.
 4. A mobile communication system in which a mobile station apparatus transmits uplink data to a base station apparatus using a physical uplink shared channel assigned by an uplink data transmission permission signal, characterized in that the base station apparatus transmits, to the mobile station apparatus, the uplink data transmission permission signal including information for instructing transmission of reception quality information without uplink data, the mobile station apparatus transmits, to the base station apparatus, reception quality information without uplink data using the physical uplink shared channel in case that the information for instructing transmission of reception quality information without uplink data is included in the uplink data transmission permission signal; and at this time, in case that ACK or NACK for downlink data needs to be transmitted, transmits, to the base station apparatus, reception quality information and ACK or NACK without uplink data.
 5. A mobile station apparatus in a mobile communication system in which the mobile station apparatus transmits reception quality information to a base station apparatus, the reception quality information indicating quality of a signal received from the base station apparatus, the mobile station apparatus characterized by comprising: an unit for receiving an uplink data transmission permission signal from the base station apparatus; and an unit for transmitting reception quality information without uplink data to the base station apparatus in case that information for instructing transmission of reception quality information without uplink data is included in the uplink data transmission permission signal, wherein in case that ACK or NACK for downlink data needs to be transmitted when transmitting reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data, the unit for transmitting the reception quality information to the base station apparatus transmits, to the base station apparatus, reception quality information and ACK or NACK without uplink data.
 6. The mobile station apparatus according to claim 5, characterized in that the unit for transmitting the reception quality information to the base station apparatus transmits, to the base station apparatus, the reception quality information and the ACK or NACK using a physical uplink shared channel.
 7. A mobile station apparatus in a mobile communication system in which the mobile station apparatus transmits reception quality information to a base station apparatus using a physical uplink shared channel, the reception quality information indicating quality of a signal received from the base station apparatus, the mobile station apparatus characterized by comprising: an unit for receiving an uplink data transmission permission signal from the base station apparatus; and an unit for transmitting reception quality information without uplink data to the base station apparatus in case that information for instructing transmission of reception quality information without uplink data is included in the uplink data transmission permission signal, wherein in case that ACK or NACK for downlink data needs to be transmitted when transmitting reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data, the unit for transmitting the reception quality information to the base station apparatus transmits, to the base station apparatus, reception quality information and ACK or NACK without uplink data.
 8. A mobile station apparatus in a mobile communication system in which the mobile station apparatus transmits uplink data to a base station apparatus using a physical uplink shared channel assigned by an uplink data transmission permission signal, the mobile station apparatus characterized by comprising: an unit for receiving the uplink data transmission permission signal from the base station apparatus; and an unit for transmitting reception quality information without uplink data using the physical uplink shared channel to the base station apparatus in case that information for instructing transmission of reception quality information without uplink data is included in the uplink data transmission permission signal, wherein in case that ACK or NACK for downlink data needs to be transmitted when transmitting reception quality information without uplink data according to the information for instructing transmission of reception quality information without uplink data, the unit for transmitting the reception quality information to the base station apparatus transmits, to the base station apparatus, reception quality information and ACK or NACK without uplink data.
 9. A communication method of a mobile station apparatus in a mobile communication system in which the mobile station apparatus transmits uplink data to a base station apparatus using a physical uplink shared channel assigned by an uplink data transmission permission signal, the communication method characterized by comprising: receiving the uplink data transmission permission signal from the base station apparatus; and transmitting reception quality information without uplink data using the physical uplink shared channel to the base station apparatus in case that information for instructing transmission of reception quality information without uplink data is included in the uplink data transmission permission signal, wherein at this time, in case that ACK or NACK for downlink data needs to be transmitted, transmitting reception quality information and ACK or NACK without uplink data to the base station apparatus. 